Types of non-melanoma skin cancer
Non-melanoma skin cancers usually develop in the outermost layer of skin (epidermis), and are often named after the type of skin cell from which they develop.
The two most common types of non-melanoma skin cancer are:
- basal cell carcinoma (BCC) – also known as a rodent ulcer, BCC starts in the cells lining the bottom of the epidermis and accounts for about 75% of skin cancers
- squamous cell carcinoma (SCC) – starts in the cells lining the top of the epidermis and accounts for about 20% of skin cancers
Basal cell carcinoma
Basal cell carcinoma (BCC) usually appears as a small, shiny pink or pearly-white lump with a translucent or waxy appearance. It can also look like a red, scaly patch.
There's sometimes some brown or black pigment within the patch.
The lump slowly gets bigger and may become crusty, bleed or develop into a painless ulcer.
Squamous cell carcinoma
Squamous cell carcinoma (SCC) appears as a firm pink lump with a rough or crusted surface. There can be a lot of surface scale and sometimes even a spiky horn sticking up from the surface.
The lump is often tender to touch, bleeds easily and may develop into an ulcer.
Bowen's disease
Bowen's disease is a precancerous form of SCC sometimes referred to as squamous cell carcinoma in situ. It develops slowly and is easily treated.
The main sign is a red, scaly patch on the skin that may itch. It most commonly affects elderly women and is often found on the lower leg. However, it can appear on any area of the skin.
Although not classed as non-melanoma skin cancer, Bowen's disease can sometimes develop into squamous cell carcinoma if left untreated.
Actinic keratoses
Actinic keratoses, also known as solar keratoses, are dry, scaly patches of skin caused by damage from years of sun exposure.
The patches can be pink, red or brown, and can vary in size from a few millimetres to a few centimetres across.
The affected skin can sometimes become very thick, and occasionally the patches can look like small horns or spikes.
Like Bowen's disease, actinic keratosis isn't classed as non-melanoma skin cancer, but there's a small risk that the patches could develop into squamous cell carcinoma if untreated.